<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <style type="text/css">
        div{
            width: 200px;
            height: 100px;
            background-image:url("img/2big.jpg");
        }
        #px{
            background-size: 100px;
            background-repeat: no-repeat;
        }
        #cover{
            background-size: cover;
        }
        #contain{
            background-size: contain;
            background-repeat: no-repeat;
        }
    </style>
</head>
<body>
<h1>background-size</h1>

<h3>像素</h3>
<div id="px"></div>

<h3>cover</h3>
<div id="cover"></div>

<h3>contain</h3>
<div id="contain"></div>
</body>
</html>